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Considerations of High Performance Roofs H1
11 May 2022
Length:
30 Minutes
Discover how to design H1-compliant roofs without unintended consequences. Learn best practices for insulation, ventilation & durability.
Featured Speakers
Shane Clarke
Scott Squire
Jon Davies
CPD points are given upon completion of the entire webinar.
Full Transcript
Nuralite Waterproofing __ Considerations of High Performance Roofs H1 transcript.docx
FAQs
How do you maintain the air gap in the ceiling space when you have two layers of insulation? Do you use some sort of clips?
There is not necessarily a need for an air gap. The detail shows layers that are independently supported on ceiling battens e.g. lofted insulation on ceiling battens or substrate e.g. PIR insulation board on plywood.
The warm roof the safest answer, as you say the cold roof/deck type systems can work but are risky as require ventilation as mentioned in Nuraply manual, is there more info around the ventilation required? As generally we see builders and owners head to the tradition cold roof due to cost, or is the cost of a warm roof similar to traditional?
There's no perfect answer here for ‘how much natural ventilation’ as it’s dependent on factors like exposure, cladding colour and weather conditions including humidity. A better answer is to avoid the problem becoming a problem – reducing or removing the amount of moisture flowing into the problem areas of insulation and air cavities. Keep moisture away from cold surfaces. For cold roof construction with Nuraply membrane systems, Nuralite supply a purpose designed Nuravent which is installed on the roof itself. We suggest 1 vent per 20sqm as conservative guidance. Bear in mind, on a small roof section we would still recommend at least 2 vents to create some cross air flow. See page 27 of the Nuraply 3PM Installation Manual for further info.
Please note, if Council ask for evidence of compliance, Nuralite cannot offer you engineering assistance in moisture control as we do not have that expertise/can't provide producer
statements.
Nuravents are not required on Nuratherm Warm Roof systems. The Nuratherm Warm Roof system on NPM 900 Metal Tray Deck is a cost effective alternative to plywood supporting roof substrate.
Oculus Architectural Engineering Ltd have an FAQ page on their website that contains resources on NZBC H1 update 2022 including ventilation.
Do you have a good line to use when builders etc. say "why do we need all these changes and increases to h1?! we don't live in Siberia!"
Until houses are easy/affordable to keep at 20C then we should all be arguing for better performing homes. It’s a good thing for people, and for reducing energy use. MBIE are looking for ways to improve our housing stock, both existing and new build. The emphasis on the H1 improvements is to reduce energy consumption. If we stay the same, we will continue to use more energy to heat and cool our buildings. This is a way pf future proofing our building stock for future generations.
How do you stop the insulation sagging into the (2) Stationary Air Gap?
The lofted insulation is supported on ceiling battens running perpendicular to the timber framing. The diagrams are indicative.
How do you achieve the air gap under the lower layer of insulation?
The lower layer of lofted insulation is supported on ceiling battens running perpendicular to the timber framing. The diagrams are indicative.
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